Postazacitidine clone size predicts long-term outcome of patients with myelodysplastic syndromes and related myeloid neoplasms

Azacitidine is a mainstay of therapy for myelodysplastic syndrome (MDS)-related diseases. The purpose of our study is to elucidate the effect of gene mutations on hematological response and overall survival (OS), particularly focusing on their posttreatment clone size. We enrolled a total of 449 patients with MDS or related myeloid neoplasms. They were analyzed for gene mutations in pretreatment (n = 449) and posttreatment (n = 289) bone marrow samples using targeted-capture sequencing to assess the impact of gene mutations and their posttreatment clone size on treatment outcomes. In Cox proportional hazard modeling, multihit TP53 mutation (hazard ratio [HR], 2.03; 95% confidence interval [CI], 1.42-2.91; P < .001), EZH2 mutation (HR, 1.71; 95% CI, 1.14-2.54; P = .009), and DDX41 mutation (HR, 0.33; 95% CI, 0.17-0.62; P < .001), together with age, high-risk karyotypes, low platelets, and high blast counts, independently predicted OS. Posttreatment clone size accounting for all drivers significantly correlated with International Working Group (IWG) response (P < .001, using trend test), except for that of DDX41-mutated clones, which did not predict IWG response. Combined, IWG response and posttreatment clone size further improved the prediction of the original model and even that of a recently proposed molecular prediction model, the molecular International Prognostic Scoring System (IPSS-M; c-index, 0.653 vs 0.688; P < .001, using likelihood ratio test). In conclusion, evaluation of posttreatment clone size, together with the pretreatment mutational profile as well as the IWG response play a role in better prognostication of azacitidine-treated patients with myelodysplasia.

Long-term follow-up after R-High CHOP/CHASER/LEED with Auto-PBSCT in untreated mantle cell lymphoma-Final analysis of JCOG0406

Progression-free survival after R-High CHOP/CHASER/LEED with auto-PBSCT in untreated mantle cell lymphoma in JCOG0406 study. A continuous pattern of relapse was observed.

Abstract 6168: Implementation and adoption of a web tool to support precision diagnostic and treatment decisions for patient with myelodysplastic syndromes

Despite a detailed understanding of the genes mutated in myelodysplastic syndromes (MDS), diagnostic and treatment decisions for patients with MDS rely primarily on clinical and cytogenetic variables as considered by the Revised International Prognostic Scoring System (IPSS-R). Here we describe the recently developed Molecular IPSS (IPSS-M), a clinico-genomic risk stratification system that considers clinical, cytogenetic and genetic parameters; the implementation of a web portal to facilitate its adoption, a strategy to handle missing variables, and the worldwide utilization of the web calculator as a clinical support tool.

The IPSS-M was trained on 2,957 clinically annotated diagnostic MDS samples profiled for mutations in 156 driver genes. To maximize the clinical applicability of the IPSS-M and account for missing genetic data (i.e genes missing from a sequencing panel), we implemented a strategy to calculate a risk score under three scenarios: best, worst and average. Last, we developed an online calculator as a standalone single-page web application using VueJs, and D3Js for the interactive visualizations, deployed through a CI/CD pipeline on AWS, where collection of anonymous usage analytics allows to track adoption and usability of the new proposed model.

The model incorporates clinical, morphological, genetic variables informed by cytogenetics and constructed from the presence of oncogenic mutations in 31 genes. It delivers a unique risk score for each individual patient, as well as an assignment to one of six IPSS-M risk strata. Compared to the IPSS-R the IPSS-M re-stratified 46% of MDS patients. The model was validated in an external dataset of 754 MDS patients. We released an open-access IPSS-M web calculator available at https://mds-risk-model.com. By specifying the patient clinical and molecular profiles, the tool returns the patient-specific IPSS-M risk score and category, and the probability estimates over time for three clinical endpoints, i.e. leukemia free survival (LFS), overall survival, and incidence of leukemic transformation. Since its launch in June 2022, the calculator has been used by &gt;6000 users in &gt;75 countries, reaching a daily average of 100 users per day. Risks have been calculated for &gt;45,000 patient profiles. 99.28% of the sessions initiated reach an IPSS-M score, suggesting that the calculator is intuitive and easy to use.

We trained and validated the IPSS-M on 3,711 patients, a patient tailored risk stratification tool for patients with MDS that considers clinical, morphological and genetic variables inclusive of cytogenetics and mutations in one of 31 genes. The development of a web based tool was instrumental to the global dissemination of the model, enabling non-expert users to leverage the power of molecular biomarkers in risk stratification for patients with MDS.

Citation Format: Elsa Bernard, Juan E. Arango Ossa, Heinz Tuechler, Peter L. Greenberg, Robert P. Hasserjian, Yasuhito Nannya, Sean M. Devlin, Maria Creignou, Philippe Pinel, Lily Monier, Juan S. Medina-Martinez, Dylan Domenico, Martin Jädersten, Ulrich Germing, Guillermo Sanz, Arjan A. van de Loosdrecht, Olivier Kosmider, Matilde Y. Follo, Felicitas Thol, Lurdes Zamora, Ronald F. Pinheiro, Andrea Pellagatti, Detlef Haase, Pierre Fenaux, Monika Belickova, Michael R. Savona, Virginia M. Klimek, Fabio P. Santos, Jacqueline Boultwood, Ioannis Kotsianidis, Valeria Santini, Francesc Solé, Uwe Platzbecker, Michael Heuser, Peter Valent, Kazuma Ohyashiki, Carlo Finelli, Maria Teresa Voso, Lee-Yung Shih, Michaela Fontenay, Joop H. Jansen, José Cervera, Norbert Gattermann, Benjamin L. Ebert, Rafael Bejar, Luca Malcovati, Mario Cazzola, Seishi Ogawa, Eva Hellström-Lindberg, Elli Papaemmanuil. Implementation and adoption of a web tool to support precision diagnostic and treatment decisions for patient with myelodysplastic syndromes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6168.

Germ line DDX41 mutations define a unique subtype of myeloid neoplasms

Germ line DDX41 variants have been implicated in late-onset myeloid neoplasms (MNs). Despite an increasing number of publications, many important features of DDX41-mutated MNs remain to be elucidated. Here we performed a comprehensive characterization of DDX41-mutated MNs, enrolling a total of 346 patients with DDX41 pathogenic/likely-pathogenic (P/LP) germ line variants and/or somatic mutations from 9082 MN patients, together with 525 first-degree relatives of DDX41-mutated and wild-type (WT) patients. P/LP DDX41 germ line variants explained ∼80% of known germ line predisposition to MNs in adults. These risk variants were 10-fold more enriched in Japanese MN cases (n = 4461) compared with the general population of Japan (n = 20 238). This enrichment of DDX41 risk alleles was much more prominent in male than female (20.7 vs 5.0). P/LP DDX41 variants conferred a large risk of developing MNs, which was negligible until 40 years of age but rapidly increased to 49% by 90 years of age. Patients with myelodysplastic syndromes (MDS) along with a DDX41-mutation rapidly progressed to acute myeloid leukemia (AML), which was however, confined to those having truncating variants. Comutation patterns at diagnosis and at progression to AML were substantially different between DDX41-mutated and WT cases, in which none of the comutations affected clinical outcomes. Even TP53 mutations made no exceptions and their dismal effect, including multihit allelic status, on survival was almost completely mitigated by the presence of DDX41 mutations. Finally, outcomes were not affected by the conventional risk stratifications including the revised/molecular International Prognostic Scoring System. Our findings establish that MDS with DDX41-mutation defines a unique subtype of MNs that is distinct from other MNs.

Amplified EPOR/JAK2 Genes Define a Unique Subtype of Acute Erythroid Leukemia

Acute erythroid leukemia (AEL) is a unique subtype of acute myeloid leukemia characterized by prominent erythroid proliferation whose molecular basis is poorly understood. To elucidate the underlying mechanism of erythroid proliferation, we analyzed 121 AEL using whole-genome, whole-exome, and/or targeted-capture sequencing, together with transcriptome analysis of 21 AEL samples. Combining publicly available sequencing data, we found a high frequency of gains and amplifications involving EPOR/JAK2 in TP53-mutated cases, particularly those having >80% erythroblasts designated as pure erythroid leukemia (10/13). These cases were frequently accompanied by gains and amplifications of ERG/ETS2 and associated with a very poor prognosis, even compared with other TP53-mutated AEL. In addition to activation of the STAT5 pathway, a common feature across all AEL cases, these AEL cases exhibited enhanced cell proliferation and heme metabolism and often showed high sensitivity to ruxolitinib in vitro and in xenograft models, highlighting a potential role of JAK2 inhibition in therapeutics of AEL.

SIGNIFICANCE

This study reveals the major role of gains, amplifications, and mutations of EPOR and JAK2 in the pathogenesis of pure erythroleukemia. Their frequent response to ruxolitinib in patient-derived xenograft and cell culture models highlights a possible therapeutic role of JAK2 inhibition for erythroleukemia with EPOR/JAK2-involving lesions. This article is highlighted in the In This Issue feature, p. 369.

Molecular International Prognostic Scoring System for Myelodysplastic Syndromes

MDS Molecular International Prognostic Scoring SystemSamples from over 2500 patients with MDS were profiled for gene mutations and used to develop the International Prognostic Scoring System-Molecular (IPSS-M). TP53multihit, FLT3 mutations, and MLLPTD were identified as top genetic predictors of adverse outcomes. IPSS-M improves prognostic discrimination across all clinical end points versus prior versions.

Potential of a sphingosine 1‑phosphate receptor antagonist and sphingosine kinase inhibitors as targets for multiple myeloma treatment

Sphingosine 1-phosphate (S1P) is a bioactive lipid involved in cancer progression through its binding to S1P receptors (S1PRs). However, the association between multiple myeloma (MM) and S1P is unclear. The current study aimed to investigate the potential anti-cancer effects of fingolimod and sphingosine kinase (SK) inhibitors in myeloma cells and the effects of S1P-induced chemoresistance and neovascularization on MM cell proliferation. MM cell lines were treated with the S1PR1 antagonist fingolimod and the SK inhibitors ABC294640 and SK1-I, after which cell proliferation was measured. Protein expression was also assessed under each condition using immunoblotting. Serum S1P levels in patients with MM, monoclonal gammopathy of undetermined significance and healthy volunteers were assessed. Human umbilical vessel cells (HUVECs) were co-cultured with anti-S1P agents to assess the effect on cell migration. All treatments suppressed myeloma cell proliferation and caspase-3-mediated apoptosis by suppressing S1P activity. These findings suggest that S1P activation is associated with proliferation and survival for MM cells. S1P attenuated the proteosome inhibitor (PI) effect, while the anti-S1P agents recovered the effect. In addition, S1P promoted the migration and proliferation of HUVECs, whereas the S1P inhibitors reduced the influence of S1P. This study highlights the therapeutic potential of anti-S1P agents for MM treatment. Inhibition of S1P function may overcome resistance to PI developed by myeloma cells and inhibit the changes to the bone marrow microenvironment via neovascularization.

A multicenter, phase II study of R-THP-COP therapy for elderly patients with newly diagnosed, advanced-stage, indolent B-cell lymphoma

The optimal combined chemotherapy regimen with rituximab has yet to be established for elderly patients with advanced-stage indolent B-cell lymphoma (B-NHL). A multicenter study was performed to evaluate the efficacy and toxicity of R-THP-COP therapy in elderly patients (aged 70–79 years) with newly diagnosed advanced-stage indolent B-NHL using the complete response rate (%CR) as the primary endpoint. Patients with newly diagnosed, clinical stage III/IV, indolent B-NHL, aged 70–79 years, with a performance status of 0–2 were eligible for this study. R-THP-COP consists of 375 mg/m² of rituximab, 50 mg/m² of pirarubicin, 750 mg/m² of cyclophosphamide, 1.4 mg/m² of vincristine, and 100 mg/day of oral prednisolone for 5 days. This study was discontinued due to poor accrual after the enrollment of 18 patients, although the planned sample size was 40 patients. The numbers of patients with follicular lymphoma, mucosa-associated lymphoid tissue lymphoma, and mantle cell lymphoma were 16, 1, and 1, respectively. The median age was 73 (range, 70 to 79) years. The %CR including unconfirmed CR was 45% (95% confidence interval: 25-66%) and the overall response rate was 72%. The estimated 5-year overall survival and progression-free survival rates were 55% and 28%, respectively. The major toxicity observed was grade 4 neutropenia (94%). Grade 4 non-hematological toxicities were not observed and no patients developed grade 3/4 cardiac toxicities. This phase II study provides useful information regarding the efficacy and toxicity of R-THP-COP therapy for patients aged 70 years or older with newly diagnosed, advanced-stage, indolent B-NHL, although the sample size was small.

Overexpression of RUNX3 Represses RUNX1 to Drive Transformation of Myelodysplastic Syndrome

RUNX3, a RUNX family transcription factor, regulates normal hematopoiesis and functions as a tumor suppressor in various tumors in humans and mice. However, emerging studies have documented increased expression of RUNX3 in hematopoietic stem/progenitor cells (HSPC) of a subset of patients with myelodysplastic syndrome (MDS) showing a worse outcome, suggesting an oncogenic function for RUNX3 in the pathogenesis of hematologic malignancies. To elucidate the oncogenic function of RUNX3 in the pathogenesis of MDS in vivo, we generated a RUNX3-expressing, Tet2-deficient mouse model with the pancytopenia and dysplastic blood cells characteristic of MDS in patients. RUNX3-expressing cells markedly suppressed the expression levels of Runx1, a critical regulator of hemaotpoiesis in normal and malignant cells, as well as its target genes, which included crucial tumor suppressors such as Cebpa and Csf1r. RUNX3 bound these genes and remodeled their Runx1-binding regions in Tet2-deficient cells. Overexpression of RUNX3 inhibited the transcriptional function of Runx1 and compromised hematopoiesis to facilitate the development of MDS in the absence of Tet2, indicating that RUNX3 is an oncogene. Furthermore, overexpression of RUNX3 activated the transcription of Myc target genes and rendered cells sensitive to inhibition of Myc-Max heterodimerization. Collectively, these results reveal the mechanism by which RUNX3 overexpression exerts oncogenic effects on the cellular function of and transcriptional program in Tet2-deficient stem cells to drive the transformation of MDS. SIGNIFICANCE: This study defines the oncogenic effects of transcription factor RUNX3 in driving the transformation of myelodysplastic syndrome, highlighting RUNX3 as a potential target for therapeutic intervention.

Effect of the extracellular component of bone marrow mesenchymal stromal cells from healthy donors on hematologic neoplasms and their angiogenesis

Bone marrow mesenchymal stromal cells (BM-MSCs) from healthy donors are a promising source of cell therapy. However, their effectiveness in cancer remains less known. This study is the first to evaluate the quality of BM-MSCs obtained from young and elderly healthy volunteers (KNT cells). The KNT cells had normal karyotypes and were positive for MSC markers (CD90, CD73, CD105). When cultured under appropriate conditions, they showed adipogenic or osteogenic potential. Hence, the anti-neoplastic effects of secretory factors [supernatant or extracellular vesicles (EV)] from KNT cells were verified using several neoplastic cells (three multiple myeloma, three myeloid leukemia, and three lymphoma cell lines). The conditioned medium (CM), but not EV, of KNT cells derived from young healthy donors significantly inhibited myeloma and lymphoma cell proliferation, but enhanced myeloid leukemia proliferation. Anti-angiogenesis effect of CM and EV derived from young KNT against hematologic neoplasia-induced angiogenesis was evident and more prominent in CM than in EV but not evident in elderly KNT-derived EV. These findings indicate that the anti-tumor effect of KNT cells depends on the types of hematologic neoplasia, with elements existing in the supernatant and not in EVs. Therefore, BM-MSC may produce soluble factors that affect cell proliferation of neoplasia, causing cell-to-cell communication. The anti-angiogenesis effect of KNT cells depends on the age of BM-MSC donors.

Downregulation of extracellular vesicle microRNA-101 derived from bone marrow mesenchymal stromal cells in myelodysplastic syndrome with disease progression

To evaluate the mechanism underlying the communication between myeloid malignant and bone marrow (BM) microenvironment cells in disease progression, the current study established BM mesenchymal stromal cells (MSCs) and assessed extracellular vesicle (EV) microRNA (miR) expression in 22 patients with myelodysplastic syndrome (MDS) and 7 patients with acute myeloid leukemia and myelodysplasia-related changes (AML/MRC). Patients with MDS were separated into two categories based on the revised International Prognostic Scoring System (IPSS-R), and EV-miR expression in BM-MSCs was evaluated using a TaqMan low-density array. The selected miRs were evaluated using reverse transcription-quantitative PCR. The current study demonstrated that the expression of BM-MSC-derived EV-miR was heterogenous and based on MDS severity, the expression of EV-miR-101 was lower in high-risk group and patients with AML/MRC compared with the control and low-risk groups. This reversibly correlated with BM blast percentage, with which the cellular miR-101 from BM-MSCs or serum EV-miR-101 expression exhibited no association. Database analyses indicated that miR-101 negatively regulated cell proliferation and epigenetic gene expression. The downregulation of BM-MSC-derived EV-miR-101 may be associated with cell-to-cell communication and may accelerate the malignant process in MDS cells.

Treatment-free remission after first-line dasatinib treatment in patients with chronic myeloid leukemia in the chronic phase: the D-NewS Study of the Kanto CML Study Group

Treatment outcomes for chronic myeloid leukemia (CML) have dramatically improved with the development of tyrosine kinase inhibitors (TKI). However, due to the improved prognosis for CML, problems have arisen from long-term administration of TKI. The present study sought to verify whether more patients could achieve treatment-free remission (TFR) after stopping the administration of dasatinib using dasatinib as frontline treatment. Treatment-naïve chronic phase CML cases were treated with dasatinib as frontline treatment. Dasatinib treatment was stopped for 26 patients who achieved deep molecular response (DMR) within 24 months and were able to maintain DMR for an additional 2 years. Ten patients (38.5%) achieved DMR maintenance after 12 months. Recurrence was confirmed in 16 patients, and the median recurrence-free survival time was 5.1 months. The cumulative DMR rates at six and 12 months after restarting treatment were 84.6% and 100%, respectively. The results of this study demonstrated that the DMR maintenance rate after 12 months was 38.5%, which was not significantly different from previous TKI stop trials. The 2-year dasatinib administration period after reaching DMR did not contribute to improve TFR rates. These results suggest that the type of TKI is not associated with better TFR rates.

A novel non-invasive monitoring assay of 5-azacitidine efficacy using global DNA methylation of peripheral blood in myelodysplastic syndrome

Purpose: Monitoring response and resistance to 5-azacitidine (AZA) is essential when treating patients with myelodysplastic syndrome (MDS). To quantify methylated DNA not only in the promoter region but also in the gene body, we established a single-molecule methylation assay (SMMA).

Patients and methods: We first investigated the methylation extent (expressed as methylation index [MI]) by SMMA among 28 MDS and 6 post-MDS acute myeloid leukemia patients. We then analyzed the MI in 13 AZA-treated patients.

Results: Whole-blood DNA from all 34 patients had low MI values compared with healthy volunteers (P<0.0001). DNA hypomethylation in MDS patients was more evident in neutrophils (P=0.0008) than in peripheral mononuclear cells (P=0.0713). No consistent pattern of genome-wide DNA hypomethylation was found among MDS subtypes or revised International Prognostic Scoring System (IPSS-R) categories; however, we found that the MI was significantly increased for patients at very high risk who were separated by the new cytogenetic scoring system for IPSS-R (P=0.0398). There was no significant difference in MI before AZA, regardless of the response to AZA (P=0.8689); however, sequential measurement of MI in peripheral blood demonstrated that AZA non-responders did not have normalized MI at the time of next course of AZA (P=0.0352).

Conclusion: Our results suggest that sequential SMMA of peripheral blood after AZA may represent a non-invasive monitoring marker for AZA efficacy in MDS patients.

Lineage-specific RUNX2 super-enhancer activates MYC and promotes the development of blastic plasmacytoid dendritic cell neoplasm

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is an aggressive subtype of acute leukemia, the cell of origin of which is considered to be precursors of plasmacytoid dendritic cells (pDCs). Since translocation (6;8)(p21;q24) is a recurrent anomaly for BPDCN, we demonstrate that a pDC-specific super-enhancer of RUNX2 is associated with the MYC promoter due to t(6;8). RUNX2 ensures the expression of pDC-signature genes in leukemic cells, but also confers survival and proliferative properties in BPDCN cells. Furthermore, the pDC-specific RUNX2 super-enhancer is hijacked to activate MYC in addition to RUNX2 expression, thereby promoting the proliferation of BPDCN. We also demonstrate that the transduction of MYC and RUNX2 is sufficient to initiate the transformation of BPDCN in mice lacking Tet2 and Tp53, providing a model that accurately recapitulates the aggressive human disease and gives an insight into the molecular mechanisms underlying the pathogenesis of BPDCN.

Copanlisib, a novel phosphoinositide 3-kinase inhibitor, combined with carfilzomib inhibits multiple myeloma cell proliferation

Multiple myeloma (MM) is a uniformly fatal disorder of B cells characterized by the accumulation of abnormal plasma cells. Phosphoinositide 3-kinase (PI3K) signaling pathways play a critical regulatory role in MM pathology. Copanlisib, also known as BAY80-6946, is a potent PI3Kα and δ inhibitor. In this study, we investigated the efficacy of copanlisib and a proteasome inhibitor using MM cell lines and primary samples. The p110α and δ catalytic subunits of the class PI3K increased, and carfilzomib activity reduced in the presence of a supernatant from the feeder cell line, HS-5. Phosphorylation of Akt and activation of caspase 3 and poly (ADP-ribose) polymerase (PARP) partially reduced upon carfilzomib treatment in the presence of HS-5. Apoptosis also decreased. Copanlisib treatment for 72 h inhibited growth in MM cell lines and induced apoptosis. Combination treatment of MM cells with carfilzomib and copanlisib caused greater cytotoxicity than that caused by either drug alone and increased apoptosis. Caspase 3 activity increased while that of Akt decreased after combination treatment with copanlisib and carfilzomib. Further, copanlisib inhibited vascular endothelial growth factor (VEGF)-mediated angiogenesis in vitro and in vivo. It also inhibited C-X-C motif chemokine 12 (CXCL12)-mediated chemotaxis. The data suggest that administration of the PI3K inhibitor, copanlisib, may be a powerful strategy against stroma-associated drug resistance of MM cells and can enhance the cytotoxic effects of proteasome inhibitors in such residual MM cells.

Chromatin Regulation by HP1γ Contributes to Survival of 5-Azacytidine-Resistant Cells

Recent investigations of the treatment for hematologic neoplasms have focused on targeting epigenetic regulators. The DNA methyltransferase inhibitor 5-azacytidine (AZA) has produced good results in the treatment of patients with myelodysplastic syndromes. The mechanism underlying its pharmacological activity involves many cellular processes including histone modifications, but chromatin regulation in AZA-resistant cells is still largely unknown. Therefore, we compared human leukemia cells with AZA resistance and their AZA-sensitive counterparts with regard to the response of histone modifications and their readers to AZA treatment to identify novel molecular target(s) in hematologic neoplasms with AZA resistance. We observed an a decrease of HP1γ, a methylated lysine 9 of histone H3-specific reader protein, in AZA-sensitive cells after treatment, whereas AZA treatment did not affect HP1 family proteins in AZA-resistant cells. The expression of shRNA targeting HP1γ reduced viability and induced apoptosis specifically in AZA-resistant cells, which accompanied with down-regulation of ATM/BRCA1 signaling, indicating that chromatin regulation by HP1γ plays a key role in the survival of AZA-resistant cells. In addition, the amount of HP1γ protein in AZA-sensitive and AZA-resistant cells was decreased after treatment with the bromodomain inhibitor I-BET151 at a dose that inhibited the growth of AZA-resistant cells more strongly than that of AZA-sensitive cells. Our findings demonstrate that treatment with AZA, which affects an epigenetic reader protein and targets HP1γ, or a bromodomain inhibitor is a novel strategy that can be used to treat patients with hematopoietic neoplasms with AZA resistance.

Clonal architecture in patients with myelodysplastic syndromes and double or minor complex abnormalities: Detailed analysis of clonal composition, involved abnormalities, and prognostic significance

The study analyzes the clonal architecture and the abnormalities involved in a series of 191 patients with myelodysplastic syndromes (MDS) and 2-3 clonal abnormalities. All patients were extracted from an international database. The patients were classified into six clonal subtypes (2A-3C) based on the number of abnormalities and the presentation of unrelated clones (UC) and/or a clonal evolution. UC were detected in 23/191 patients (12%). The composition of UC showed great variability. The only recurrent combination of abnormalities was del(5q) and + 8 in 8 of 23 patients (35%). In patients with clonal evolution, the clone size of the primary and secondary clone varied: Patients with -7 and + 8 in the primary clone showed a larger primary and a smaller secondary clone (-7: median 74% vs 10%; +8 73% vs 18%) while patients with del(5q) in the primary clone showed a smaller primary and a larger secondary clone (33% vs 61%). Univariate and multivariate analyses showed no significant differences regarding overall or AML-free survival between the clonal subtypes. Only the subtype 3C (3 abnormalities and clonal evolution) was an independent risk factor for developing AML (Hazard Ratio 5.5 as compared to subtype 2A, P < .05). Finally, our study confirms that the number of abnormalities clearly defines a significant risk factor for overall- as well as AML-free survival. Importantly, in patients with more than one clone, the calculation of the number of abnormalities in the entire sample instead of the number of abnormalities per clone allows a higher prognostic accuracy.

Cardiac biopsy with intracardiac echocardiographic guidance for successful diagnosis of cardiac lymphoma

The diagnosis and appropriate treatment of cardiac lymphoma are often delayed by the difficulty in obtaining heart tissue biopsies. Intracardiac echocardiography-guided biopsy can improve the prognosis of cardiac lymphoma by decreasing postbiopsy complications and increasing biopsy quality, allowing collection of sufficient material for multilateral analysis.

Exosomal miRNA Signatures for Late-Onset Acute Graft-Versus-Host Disease in Allogenic Hematopoietic Stem Cell Transplantation

Recent studies have demonstrated that exosomal microRNAs (miRNAs) have the potential of facilitating molecular diagnosis. Currently, little is known about the underlying mechanism behind late-onset acute graft-versus-host disease (LA GVHD). Identifying differentially expressed miRNAs in exosomes should be useful for understanding the role of miRNAs in this disease. This study was established to investigate the relevance of miRNAs in exosomes derived from patients developing LA GVHD after allogeneic hematopoietic stem cell transplantation (HSCT). Plasma samples were collected from patients with LA GVHD (n = 5), non-GVHD (n = 5), and controls (n = 8) for exosomal miRNA expression profiling using a TaqMan low-density array; the results were validated by quantitative reverse transcription polymerase chain reaction (RT-PCR). We analyzed exosomal miRNAs differentially expressed among these three groups. MirTarBase was employed to predict potential target genes of the miRNAs specific for LA GVHD. We detected 55 miRNAs that were differentially expressed with a significant change >2.0-fold between LA GVHD and non-GVHD. Of these, we selected the 10 miRNAs (miR-423-5p, miR-19a, miR-142-3p, miR-128, miR-193b, miR-30c, miR-193a, miR-191, miR-125b, and miR-574-3p) with the most significant differential expression. Using quantitative RT-PCR, we further identified that miR-128 was significantly upregulated at the onset of LA GVHD compared with that in normal controls and is a promising diagnostic marker of LA GVHD, with an area under the curve (AUC) value of 0.975. MirTarBase analysis revealed that the predicted target genes of miR-128 are involved in the immune system and inflammation. Increased expression of miR-128 may serve as a novel, noninvasive biomarker for early LA GVHD diagnosis.

Therapeutic targeting of Aurora A kinase in Philadelphia chromosome-positive ABL tyrosine kinase inhibitor-resistant cells

Abelson murine leukemia viral oncogene homolog (ABL) tyrosine kinase inhibitors (TKIs) have been shown to be effective for treatment of chronic myeloid leukemia (CML) and Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia patients. However, resistance to ABL TKIs can develop as a result of breakpoint cluster region-ABL point mutations. Aurora kinases regulate many processes associated with mitosis. In this study, we investigated whether inhibiting Aurora kinase can reduce the viability of Ph+ leukemia cells. Treatment with the Aurora kinase A inhibitor alisertib blocked Ph+ leukemia cell proliferation and Aurora kinase A phosphorylation; it also induced G2/M-phase arrest and increased the intracellular levels of reactive oxygen species. Combined treatment of Ph+ cells with ABL TKIs and alisertib was cytotoxic, with the fraction of senescent cells increasing in a time- and dose-dependent manner. Aurora A gene silencing suppressed cell proliferation and enhanced ABL TKI efficacy. In a mouse xenograft model, co-administration of ponatinib and alisertib enhanced survival and reduced tumor size; moreover, the treatments were well tolerated by the animals. These results indicate that inhibiting Aurora kinase can enhance the cytotoxic effects of ABL TKIs and is, therefore, an effective therapeutic strategy against ABL TKI-resistant cells, including those with the T315I mutation.

R-High-CHOP/CHASER/LEED with autologous stem cell transplantation in newly diagnosed mantle cell lymphoma: JCOG0406 STUDY

Although induction immunochemotherapy including high‐dose cytarabine and rituximab followed by high‐dose chemotherapy (HDC) with autologous stem cell transplantation (ASCT) is recommended for younger patients (≤65 years old) with untreated mantle cell lymphoma (MCL), no standard induction and HDC regimen has been established. We conducted a phase II study of induction immunochemotherapy of R‐High‐CHOP/CHASER followed by HDC of LEED with ASCT in younger patients with untreated advanced MCL. Eligibility criteria included untreated MCL, stage II bulky to IV, and age 20‐65 years. Patients received 1 cycle of R‐High‐CHOP followed by 3 cycles of CHASER every 3 weeks. Peripheral blood stem cells (PBSC) were harvested during CHASER. LEED with ASCT was delivered to patients who responded to R‐High‐CHOP/CHASER. Primary endpoint was 2‐year progression‐free survival (PFS). From June 2008 to June 2012, 45 patients (median age 59 years; range 38‐65 years) were enrolled. PBSC were successfully harvested from 36 of 43 patients. Thirty‐five patients completed ASCT. Two‐year PFS was 77% (80% CI 68‐84), which met the primary endpoint. Five‐year PFS and overall survival were 52% (95% CI 34‐68%) and 71% (95% CI 51‐84%), respectively. Overall response and complete response rates after induction immunochemotherapy were 96% and 82%, respectively. The most common grade 4 toxicities were hematological. In younger patients with untreated MCL, R‐High‐CHOP/CHASER/LEED with ASCT showed high efficacy and acceptable toxicity, and it can now be considered a standard treatment option.

HIV positivity may not have a negative impact on survival in Epstein-Barr virus-positive Hodgkin lymphoma: A Japanese nationwide retrospective survey

There has been no comparative clinical study focused on differences in the clinical features of Epstein-Barr virus (EBV)⁺ Hodgkin lymphoma (HL) between HIV-positive and -negative cases. In a nationwide survey from 511 institutions in Japan, the present study investigated 16 EBV+ HIV^positive HL patients. To further clarify their characteristics in comparison with EBV+ HIV^negative HL (n=34) in the combination antiretroviral therapy era in Japan, the present study was performed. Results indicated that EBV⁺ HIV^positive HL frequently occurred in a younger population compared with EBV⁺ HIV^negative HL (P=0.0295), and that the EBV⁺ HIV^positive HL group was not associated with the nodular sclerosis subtype in the population who were below the age of 40. Notably, the EBV⁺ HIV^positive HL group had a significantly higher frequency of extra-nodal involvement (P=0.0214), including marrow invasion. In the advanced stage, 80% of those with EBV⁺ HIV^positive HL did not require dose-reduction and in the majority of cases, chemotherapy was completed. There were no significant differences in the complete remission rate (P=0.1961), overall survival (P=0.200) and progression-free survival (P=0.245) between EBV⁺ HIV^positive HL (median observational period, 23.5 months) and EBV⁺ HIV^negative HL (median observational period, 64.5 months), suggesting that HIV positivity may not have a negative impact on the clinical outcome of EBV⁺ HL. Notably, standard chemotherapy is effective and tolerable for EBV⁺ HL, regardless of HIV infection.

Extracellular vesicle-mediated cell-cell communication in haematological neoplasms

Crosstalk between bone marrow tumour cells and surrounding cells, including bone marrow mesenchymal stromal cells (BM-MSCs), endothelial cells and immune cells, is important for tumour growth in haematological neoplasms. In addition to conventional signalling pathways, extracellular vesicles (EVs), which are endosome-derived vesicles containing proteins, mRNAs, lipids and miRNAs, can facilitate modulation of the bone marrow microenvironment without directly contacting non-tumourous cells. In this review, we discuss the current understanding of EV-mediated cell-cell communication in haematological neoplasms, particularly leukaemia and multiple myeloma. We highlight the actions of tumour and BM-MSC EVs in multiple myeloma. The origin of EVs, their tropism and mechanism of EV transfer are emerging issues that need to be addressed in EV-mediated cell-cell communication in haematological neoplasms.This article is part of the discussion meeting issue 'Extracellular vesicles and the tumour microenvironment'.

[Human herpesvirus-6 pneumonitis following autologous peripheral blood stem cell transplantation]

A-46-year-old man was diagnosed with peripheral T cell lymphoma, not otherwise specified. He achieved a complete remission after pirarubicin, cyclophosphamide, vincristine, and prednisolone (THP-COP) therapy and successful autologous peripheral blood stem-cell transplantation (AutoSCT). However, 6 months post AutoSCT, he complained of fever. Chest computed tomography of the patient displayed bilateral interstitial pneumonitis. Human herpesvirus-6 (HHV-6) DNA was detected in his bronchoalveolar lavage fluid. Therefore, the patient was confirmed for HHV-6 pneumonitis. The treatment with foscarnet was effective, and no relapse was noticed in the patient. Besides, we have experienced pneumonitis of unknown origin in some patients after autologous or allogeneic stem-cell transplantations. Moreover, most of the above patients were clinically diagnosed using serum or plasma markers. Therefore, examining respiratory symptoms after AutoSCT would enable a more accurate diagnosis as well as treatment of patients with HHV-6 pneumonitis.

Therapeutic effects of tyrosine kinase inhibitors and subtypes of BCR-ABL1 transcripts in Japanese chronic myeloid leukemia patients with three-way chromosomal translocations

We analyzed the clinical responses to thyrosine kinase inhibitors (TKIs) and the molecular and cytogenetic characteristics of 18 chronic myeloid leukemia (CML) patients with 3-way chromosomal translocations. The patients were 14 men and 4 women, aged 23-75 years (median 57 years). The Sokal risk was low in 12 patients, intermediate in 4 patients, and high in 2 patients. Newly identified translocation breakpoints were seen in 7 of the 18 patients. Three patients had the same breakpoints of t(9;22;11)(q34;q11.2;q23). The best responses to TKIs were partial cytogenic response (PCyR) in 2 patients, complete cytogenic response (CCyR) in 3 patients, molecular response (MR) 3.0 in 7 patients, MR 4.0 in 3 patients, and MR 4.5 or higher in 3 patients. A total of 66.7% of patients did not achieve MR 4.0 or higher. In 3 patients in whom TKIs resulted in MR 4.5 or higher for more than 2 years, TKI treatment was discontinued. However, all of them exhibited a loss of MR3.0, at 2, 6, and 20 months after the discontinuation of treatment, respectively, and TKI treatment needed to be restarted. According to Kaplan-Meier survival curve analysis, the overall survival (OS) was 100 months in 56% of the patients. The 60-months cumulative incidences of CCyR, MR3.0, MR4.0 and MR4.5 were 88.9%, 72.2%, 33.3%, and 16.7%, respectively. In the 11 analyzable patients, the BCR-ABL1 mRNA subtype was e14a2 type in 4 patients and e13a2 type in 7 patients.

Phase 1/2 study of the WT1 peptide cancer vaccine WT4869 in patients with myelodysplastic syndrome

WT4869 is a synthetic peptide vaccine derived from the Wilms’ tumor gene 1 (WT1) protein. This phase 1/2 open‐label study evaluated the safety and efficacy of WT4869, and biomarkers for response, in patients with myelodysplastic syndrome. WT4869 (5–1200 μg/dose) was administered intradermally every 2 weeks, according to a 3 + 3 dose‐escalation method in higher‐risk (International Prognostic Scoring System score ≥1.5) or lower‐risk (score <1.5) red blood cell transfusion‐dependent patients with myelodysplastic syndrome. Twenty‐six patients were enrolled and treated (median age, 75 years; range, 32 to 89). The most common adverse event was injection site reaction (61.5%). Main grade 3 or 4 adverse events were neutropenia (30.8%), febrile neutropenia, pneumonia, elevated blood creatine phosphokinase levels and hypoalbuminemia (all 7.7%). Dose‐limiting toxicities occurred in 1 patient in the 50 μg/dose cohort (pyrexia, muscle hemorrhage and hypoalbuminemia) and 1 patient in the 400 μg/dose cohort (pneumonitis); however, the maximum tolerated dose could not be determined from this trial. The overall response rate was 18.2%, the disease control rate was 59.1% and median overall survival was 64.71 weeks (95% confidence interval: 50.29, 142.86) as assessed by the Kaplan–Meier method. Subgroup analysis of azacitidine‐refractory patients with higher‐risk myelodysplastic syndrome (11 patients) showed median overall survival of 55.71 weeks (approximately 13 months). WT1‐specific cytotoxic T lymphocyte induction was observed in 11 of 25 evaluable patients. WT4869 was well tolerated in patients with myelodysplastic syndrome and preliminary data suggest that WT4869 is efficacious. This trial was registered at www.clinicaltrials.jp as JapicCTI‐101374.

Genetic variations of bone marrow mesenchymal stromal cells derived from acute leukemia and myelodysplastic syndrome by targeted deep sequencing

Bone marrow mesenchymal stromal cells (MSCs), which support proliferation and differentiation of hematopoietic stem cells, may play a crucial role in the pathogenesis of myeloid neoplasms. To determine whether MSCs in myeloid neoplasms harbor distinct somatic mutations that may affect their function, we used a targeted gene sequencing panel containing 50 myeloid neoplasm-associated genes with coverage of ≥500. We compared the genetic alterations between MSCs and bone marrow hematopoietic (BM) cells from patients with acute leukemia (n=5) or myelodysplastic syndrome (MDS, n=5). Non-synonymous somatic mutations, such as DNMT3A-R882H and FLT3-D835Y, were only detected in BM cells with high allelic frequency. We found several non-synonymous genetic variants overlapping BM cells and MSCs, including TP53 and ASXL1, partially owing to the heterogenous cell fraction of MSC samples and lineage fidelity. We also found MSC-specific genetic variants with very low allelic frequency (7% to 8%), such as NF1-G2114D and NF1-G140. Further studies in large cohorts are needed to clarify the molecular properties of MSCs including age-related genetic alterations by targeted deep sequencing.

Teriflunomide restores 5-azacytidine sensitivity via activation of pyrimidine salvage in 5-azacytidine-resistant leukemia cells

Previous studies showed that downregulation of pyrimidine salvage underlies resistance against 5-azacytidine (AZA), indicating an important role for de novo pyrimidine synthesis in AZA resistance. Because de novo pyrimidine synthesis is inhibited by the immunomodulator teriflunomide and its pro-drug leflunomide, we examined the effect of combined treatment with AZA and teriflunomide on AZA resistance to develop a novel strategy to cancel and prevent AZA resistance. Teriflunomide markedly inhibited the growth of AZA-resistant human leukemia cell lines (R-U937 and R-HL-60) in comparison with their AZA-sensitive counterparts (U937 and HL-60). In the presence of a non-toxic concentration of teriflunomide (1 μM), AZA induced apoptosis in AZA-resistant cells and leukemia cells from AZA-resistant patients. AZA acted as a DNA methyltransferase 3A inhibitor in AZA-resistant cells in the presence of 1 μM teriflunomide. Although AZA-sensitive cells acquired AZA resistance after continuous treatment with AZA for 42 days, the growth of AZA-sensitive cells continuously treated with the combination of AZA and teriflunomide was significantly inhibited in the presence of AZA, demonstrating that the combined treatment prevented AZA resistance. These results suggest that combined treatment with AZA and teriflunomide can be a novel strategy to overcome AZA resistance.

BCR-ABL1-positive chronic myeloid leukemia emerging in a patient with secondary myelofibrosis harboring the JAK2-V617F mutation

A 53-year-old woman with a 27-year history of myeloproliferative neoplasms came to our hospital because of a marked white blood cell count increase and progressive anemia. Clinical examination demonstrated positivity for BCR-ABL1 and JAK2-V617F mutations. She was given a diagnosis of chronic myeloid leukemia. Using the international scale, a molecular response (MR) ^4.5 was achieved after treatment with dasatinib, despite the persistence of marked splenomegaly. The pathological findings of myelofibrosis were demonstrated by bone marrow biopsy. After stopping dasatinib administration for 4 years and 5 months, treatment with ruxolitinib was started. Five months later, the size of her spleen was reduced. We speculated that translocation of BCR-ABL1 might have occurred in a sub-clone of the JAK2-V617F mutated tumor clone.

Up-regulated exosomal miRNA-140-3p in CML patients with musculoskeletal pain associated with discontinuation of tyrosine kinase inhibitors

We analyzed the exosomal miRNA from peripheral blood from CML patients with musculoskeletal pain after stopping tyrosine kinase inhibitors to identify possible factors related to this manifestation. Exosomal miRNA profiling using TaqMan low-density array revealed that exosomal miR-140-3p was significantly elevated in CML patients showing musculoskeletal pain, when compared to those without such pain (P = 0.0336) or healthy individuals (P = 0.0022). All five CML patients with musculoskeletal pain and increased exosomal miR-140-3p levels sustained deep molecular responses: four of them achieved symptom relief and a significant decrease in exosomal miR-140-3p levels was evident. Because exosomal miR-140-3p is considered to have an inflammation-associated biological function in airway smooth muscle cells and targets Myomarker muscle-specific transmembrane protein, it appears that its overexpression in circulating exosomal miR-140-3p may have some role in the mechanism underlying self-limited musculoskeletal pain.

Musculoskeletal pain after stopping tyrosine kinase inhibitor in patients with chronic myeloid leukemia: a questionnaire survey

We conducted a questionnaire survey to assess the state of patients with CML after discontinuation of TKI therapy. Nine of 27 patients developed musculoskeletal pain after TKI discontinuation. One had discontinued nilotinib and eight had discontinued imatinib therapy. Median time to symptom development after discontinuation was 2 weeks. Four experienced grade 3 symptoms as per the CTCAE ver. 4.0. One had pain persisting over a period of 21 months. There was a significant difference between patients with and without symptoms as regards female gender and the probability of persistent MMR. Awareness of this withdrawal syndrome after TKI discontinuation is imperative.

Poly (ADP-ribose) polymerase inhibitors selectively induce cytotoxicity in TCF3-HLF-positive leukemic cells

Poly (ADP-ribose) polymerase (PARP) is an indispensable component of the DNA repair machinery. PARP inhibitors are used as cutting-edge treatments for patients with homologous recombination repair (HRR)-defective breast cancers harboring mutations in BRCA1 or BRCA2. Other tumors defective in HRR, including some hematological malignancies, are predicted to be good candidates for treatment with PARP inhibitors. Screening of leukemia-derived cell lines revealed that lymphoid lineage-derived leukemia cell lines, except for those derived from mature B cells and KMT2A (MLL)-rearranged B-cell precursors, were relatively sensitive to PARP inhibitors. By contrast, acute myelogenous leukemia cell lines, except for RUNX1-RUNXT1 (AML1-ETO)-positive lines, were relatively resistant. Intriguingly, TCF3 (E2A)-HLF-positive leukemia was sensitive to PARP inhibitors. TCF3-HLF expression suppressed HRR activity, suggesting that PARP inhibitor treatment induced synthetic lethality. Furthermore, TCF3-HLF expression decreased levels of MCPH1, which regulates the expression of BRCA1, resulting in attenuation of HRR activity. The PARP inhibitor olaparib was also effective in an in vivo xenograft model. Our results suggest a novel therapeutic approach for treating refractory leukemia, particularly the TCF3-HLF-positive subtype.

Association of pleural effusion with an early molecular response in patients with newly diagnosed chronic-phase chronic myeloid leukemia receiving dasatinib: Results of a D-First study

Despite the efficacy and safety of dasatinib treatment for chronic-phase chronic myeloid leukemia (CML-CP), adverse effects such as pleural effusion (PE) are still a serious concern. We determined the clinical significance of PE incidence using patient data derived from the D-First clinical study. In the present study, chest radiography and quantification of specific lymphocyte subsets were performed routinely after initiation of dasatinib treatment. Among 52 patients with newly diagnosed CML-CP, 17 (33%) developed PE within 18 months after initial dasatinib administration, but all cases were moderate (Grade 1, 10 patients; Grade 2, 7 patients). CD56+ lymphocyte counts at 1 month correlated significantly with the incidence of PE, whereas lymphocytosis did not. The major molecular response (MMR) rate at 3 months (although not at later times) was significantly higher in PE-positive patients than PE-negative patients (59% versus 24%, respectively; P=0.013). Deep molecular response rates did not differ significantly between the PE groups at any time point during the observation period. Our results suggest that an immune-mediated mechanism involving natural killer cells underlies the development of PE in patients receiving dasatinib for 18 months. This mechanism likely promotes transient tumor regression in patients newly diagnosed with CML-CP.